package com.example.flinktest.wordcount;

import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.util.Collector;

import java.util.Arrays;

public class BoundedStreamWordCount {
    public static void main(String[] args) throws Exception {
        //创建流式执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        //读取文件
        DataStreamSource<String> lineDS = env.readTextFile("input/words.txt");
        //转换数据格式
        SingleOutputStreamOperator<Tuple2<String, Long>> wordAndOne = lineDS.flatMap(
                        (String line, Collector<String> words) -> {
                            Arrays.stream(line.split(" ")).forEach(words::collect);
                        }).returns(Types.STRING).map(word -> Tuple2.of(word, 1L))
                .returns(Types.TUPLE(Types.STRING, Types.LONG));
        //分组
        KeyedStream<Tuple2<String, Long>, String> ks = wordAndOne.keyBy(t -> t.f0);
        //求和
        SingleOutputStreamOperator<Tuple2<String, Long>> result = ks.sum(1);
        //打印
        result.print();
        //执行
        env.execute();
    }
}
